Calculation example: how much CO2 does a tree absorb?

Let's look at an example. Take a 1000 kg tree with 100% moisture content. This tree is 500 kg water and 500 kg dry mass. 47.5% of that dry mass is carbon. That's 237.5 kg.

Thanks to molar mass ratios, we can break down CO₂. For instance, it takes 3.67 kg of CO₂ to create 1 kg of carbon in a tree. This is because CO₂ has a molar mass of 12 and oxygen 16. As carbon dioxide, that is 44. And 44/12 = 3.67.

For our example: 237.5 × 3.67 = 871.63 kg CO₂. Hooray! If we want to know how much is absorbed per year, we need to know the age. A one-ton tree that took about 44 years to develop this mass will thus absorb an average of 20 kg of CO₂ per year (871.63/44=20).